feature: Convert `Unpack[TypedDict]` to regular arguments

[llucax]

Is your feature request related to a problem? Please describe.

Not a problem, but when writing functions/classes with lots of options, and in particular when these options need to be forwarded down to a few levels, it is extremely convenient to use Unpack[TypeDict] as the type for keyword arguments and group all arguments in a class that can be reused.

For example:

from typing import TypedDict, Unpack

class Args(TypedDict):
    """Arguments for the add function"""

    a: int
    """The first number"""
    b: int
    """The second number"""

def add(**args: Unpack[Args]) -> int:
    """Add two numbers together.

    Args:
        **args: The arguments for the function.

    Returns:
        The sum of the two numbers.
    """
    return args["a"] + args["b"]

Renders as:

Describe the solution you'd like

It would be nice if it were rendered as regular arguments instead, like:

Describe alternatives you've considered

They are basically above.

Additional context

I know this might be tricky, specially considering cases using Args(TypeDict, total=False) or NotRequired as in this case some arguments could not be present at all, which is different from passing None for example. But maybe there is a low hanging fruit, and at least some limited support could be added.

[pawamoy]

Thanks for the request @llucax! Related: mkdocstrings/griffe#284.

[llucax]

Oh, thanks for the reference, I completely missed it. I was actually in doubt if it had to be reported in griffe or not 🤷

[pawamoy]

No worries, it's not a duplicate. Support for Unpack must be implemented in Griffe, but here we also want an option to actually unpack the signature when rendering 🙂

[Kludex]

This would be very nice. I was going to ask about it.

[samuelcolvin]

This would be great plase @pawamoy.